Today, we have a *very* informative guest post by Mike Freiberg. Mike is a staff writer for HomeDaddys, a resource for stay-at-home dads, work-at-home dads, and everything in between. He’s a handyman, an amateur astronomer, and a tech junkie, who loves being home with his two kids. He lives in Austin.
It isn’t the biggest, or the flashiest—but it’s definitely the priciest
The new One World Trade Center (or Freedom Tower) has been a difficult project to get moving since it was announced nearly twelve years ago. Numerous architects and dozens of possible designs were considered, and ultimately scrapped, as the project underwent one reinvention after another. The project was finally completed May 10th of this year, rising to a symbolic 1,776 feet, and running up a bill of just under $4 billion—making it (by far) the most expensive skyscraper ever built.
For comparison, the Burj Khalifa, currently the tallest building in the world, dwarfs One WTC by over 1,000 feet, and is much more lavishly appointed—but was built for less than half the price ($1.5 billion). So where did One World Trade Center’s nearly $4 billion price tag come from?
The world’s first fortress skyscraper
The Freedom Tower designers had to juggle several competing priorities. The tower shouldered a heavy rhetorical burden, as a symbol of fortitude and resilience—but it also had to meet the pragmatic needs of a global financial hub on an extremely valuable piece of real estate. It was a tall order; but by far the most expensive and challenging aspect of Freedom Tower’s design was security—demonstrating that the lessons of the 9/11 attacks would be taken seriously.
From the exterior, One World Trade Center looks like any other skyscraper. Inside, though, it’s built like a tank—and incorporating (and concealing) these features was the greatest source of cost overruns during the tower’s seven-year build. Here are a few of the most impressive innovations.
A towering concrete base
Unlike most skyscrapers, One World Trade Center is set on a 20-story, windowless podium of highly reinforced concrete, built to withstand a 1,500 lb. truck bomb of the type used in the 1993 World Trade Center bombing. When completed, the podium will be sheathed in prismatic glass to conceal the blast walls. The podium uses 720,000 cubic feet of “iCrete”, an expensive designer concrete mixture capable of withstanding 14,000 pounds per square inch of pressure—nearly three times the compressive strength of normal high-rise concrete.
A colossal air-quality apparatus
While the exterior is fortified against explosions and impact, designers also considered the threat of biological and chemical attacks, as well as fire, sparing no expense for One World Trade Center’s internal air system. Each stairwell is composed of reinforced concrete, with a separate, pressurized air supply to keep them operational in the event of an emergency.
The building is also dotted with biological and chemical filters and detectors, as well as ventilation shafts that can quickly expel contaminants as soon as they are detected.
Fortified, secure elevator shafts
One World Trade Center’s elevators are encased in three feet of concrete, and serve as an internal “spine” for the building, to prevent collapse in the event that the steel exoskeleton gives way (as it did in the September 11th attacks). The tower contains 71 elevators, none of which have buttons—instead, the car identifies each passenger, and will only bring them to the floor for which they are authorized, at an impressive 23 miles per hour. It remains to be seen how smoothly this system will operate—the building will open late this year.
An integrated security and safety network
Perhaps unsurprisingly, Freedom Tower will feature over 400 closed-circuit surveillance cameras, networked security doors, temperature and air quality monitors, and automated elevators connected via a huge web of shielded communications cables. Security teams will have a constant stream of richly-detailed status reports from across the building, so that even minor problems like electrical failures or a buzzing smoke detector reach security instantaneously. Early on, this security grid will also incorporate airport-style checkpoints and electrified fencing on the tower grounds, but those measures will be phased out after several months of normal operation.
Of course, these mammoth security expenses have been highly controversial—what seems like an appropriate symbol of vigilance to some, manifests paranoia to others—but however you interpret them, it’s not all that surprising that One World Trade Center is now the world’s most expensive skyscraper.
Thanks, Mike, for the detailed information on the newest symbol in the NYC skyline.
What do you think about the Freedom Tower? Is it money well spent? Over-engineered to death? Share in the comments section, below.
As many of you may be aware, the North Carolina legislature was considering a bill that would effectively take away the option of LEED certification for public projects. In a misguided effort to protect the NC timber industry, the original bill would essentially take away the option of using LEED for public projects.
Thanks to the strong potests from many industry groups, and the great coverage of the issue by Bob Kruhm and the folks at his paper NC Construction News, the NC Senate passed an amended version of House Bill 628 on Monday night that retains the option of LEED certifciation for State construction projects. Read the full story here. [For the original bill and other versions, click here].
How many bridges do you drive over on your way to work each day? Probably a bunch, if you have the typical commute of 32 round trip miles per day. Now, how many of them are *not* structurally sound? Probably more than you realize.
The American Society of Civil Engineers (ASCE) has just released its American Infrastructure Report Card. Overall, the nation scored a miserable overall D+. Here’s the breakdown for the Transportation categories:
In the breakout for North Carolina,
- 2,192 of the 18,165 (12.1%) bridges in North Carolina are considered structurally deficient.
- 3,296 of the 18,165 (18.1%) bridges in North Carolina are considered functionally obsolete.
The report has a ton of interactive information, including a nation-wide county by county deficient bridges look up, identifying infrastructure defects in detail. Currently, much of the planned infrastructure improvements is in limbo while the sequester is in effect. However, our nation’s system of deficient bridges must be a priority. Will it take another event similar to Minnesota’s I-35 bridge collapse before we fix our nation’s infrastructure? Let’s hope not.
Your turn. What are your thoughts about the current infrastructure of America’s roads and bridges?
Engineers who design in earthquake-prone areas know that they need to design the seismic loads of their bridges to account for potential massive shifts during a quake. (This is what is legally known as the professional standard of care, which takes into account what similar engineers, in the same conditions and community, would consider acceptable design)**. The Dumbarton Bridge, the farthest south bridge across the San Francisco Bay, is no exception to this rule.
Currently, the Dumbarton Bridge is being renovated as part of the San Francisco Bay Area Toll Bridge Seismic Retrofit Program. When the bridge is finished (expected in early 2013), the bridge will increase its ability to move from 20 inches of lateral movement to as much as 42 inches of lateral movement.
The retrofit includes friction pendulum bearings designed by Earthquake Protection Systems, Inc., which will isolate the superstructure from two pier structures where the main span of the bridge meets the approach structures. A concrete taper will be used from the joints to the main span to ease the transition, as the approach span is 5 inches lower than the main span.
According to Earthquake Protection Systems president Victor Zayas, in a statement to Roads & Bridges magazine, the most critical part of the bearing is the bottom lining, which is a self-sacrificing, solid-lubricant polymer composite that was developed based on earlier research done by NASA in the 1960s.
Click here to read more on the Dumbarton Bridge retrofit.
** If you missed my post on the jury instruction on standard of care, be sure to check it out here.
Photo (c) Jill Clardy via CC.
Today, a guest post from Kristie Lewis, freelance writer for Construction Management Degree. Kristie has written numerous articles on both construction training and education as well as industry news and trends. In her spare time, Kristie enjoys cooking in her newly remodeled kitchen and reading science fiction novels. You can reach out to her at Kristie.Lewis81@gmail.com. Thanks for sharing, Kristie.
In an effort to protect the rights of employers in all industries, the federal government has enacted several labor laws. Some of the laws apply to all business sectors, and some apply to specific industries, such as construction.
Although those who earn a degree from an accredited construction management program will be required to learn about a variety of laws that apply to the construction industry, it is never a bad idea to review the details of them. Here are four labor laws that every construction manager should know like the back of their hand.
The Fair Labor Standards Act (FLSA)
This act sets the standards for wages and overtime pay. In general, it requires employers to pay covered employees who are not otherwise exempt at least the federal minimum wage and pay 1.5 times the regular rate for overtime hours. The Fair Labor Standards Act is administered by the Wage and Hour Division. More information on this law can be found at the division’s official website.
Davis-Bacon and Related Acts
These policies apply to contractors and subcontractors that are working on public buildings or public works projects that are federally funded and will cost more than $2,000 to construct, alter or repair. According to the act, contractors and subcontractors must pay their laborers and mechanics employed under the contract no less than the locally prevailing wages and fringe benefits for corresponding work on similar projects in the area. There are additional details that can also be found on the Wage and Hour Division’s official website.
The Occupational Safety and Health Act (OSHA)
This act is administered by the Occupational Safety and Health Administration and includes an array of industry-specific regulations that are enforced through regular workplace inspections and investigations. Compliance assistance and other cooperative programs are available for employers who request help. Although there seems to be an endless amount of rules to comply with, most of them are common sense rules that smart construction managers already abide by. Still, it is wise to make sure your project is congruent with the federal law, because any infractions can be found through inspection or reported by a worker.
The Labor-Management Reporting and Disclosure Act (LMRDA) of 1959
This law deals with the relationship between a union and its members. Also known as the Landrum-Griffin Act, it protects union funds and promotes union democracy by requiring labor organizations to file annual financial reports. Employers are also required to file reports regarding certain labor practices. It is administered by the Office of Labor-Management Standards. You can read the details of the law here.
Knowing the details of the above laws will not only keep your construction business safe from legal trouble, it will also allow you to provide your employers with the best working environment possible.
Questions on these laws, or comments? Drop Kristie and me a note in the comment section, below.
Photo: (c) Anna Strumillo.